NDUFV1-Related Mitochondrial Complex-1 Disorders: A Retrospective Case Series and Literature Review.

BACKGROUND: Pathogenic variants in the NDUFV1 gene disrupt mitochondrial complex I, leading to neuroregression with leukoencephalopathy and basal ganglia involvement on neuroimaging. This study aims to provide a concise review on NDUFV1-related disorders while adding the largest cohort from a single center to the existing literature. METHODS: We retrospectively collected genetically proven cases of NDUFV1 pathogenic variants from our center over the last decade and explored reported instances in existing literature. Magnetic resonance imaging (MRI) patterns observed in these patients were split into three types-Leigh (putamen, basal ganglia, thalamus, and brainstem involvement), mitochondrial leukodystrophy (ML) (cerebral white matter involvement with cystic cavitations), and mixed (both). RESULTS: Analysis included 44 children (seven from our center and 37 from literature). The most prevalent comorbidities were hypertonia, ocular abnormalities, feeding issues, and hypotonia at onset. Children with the Leigh-type MRI pattern exhibited significantly higher rates of breathing difficulties, whereas those with a mixed phenotype had a higher prevalence of dystonia. The c.1156C>T variant in exon 8 of the NDUFV1 gene was the most common variant among individuals of Asian ethnicity and is predominantly associated with irritability and dystonia. Seizures and Leigh pattern of MRI of the brain was found to be less commonly associated with this variant. Higher rate of mortality was observed in children with Leigh-type pattern on brain MRI and those who did not receive mitochondrial cocktail. CONCLUSIONS: MRI phenotyping might help predict outcome. Appropriate and timely treatment with mitochondrial cocktail may reduce the probability of death and may positively impact the long-term outcomes, regardless of the genetic variant or age of onset.

NDUFV1 attenuates renal ischemia-reperfusion injury by improving mitochondrial homeostasis.

Impaired mitochondrial function and dysregulated energy metabolism have been shown to be involved in the pathological progression of kidney diseases such as acute kidney injury (AKI) and diabetic nephropathy. Hence, improving mitochondrial function is a promising strategy for treating renal dysfunction. NADH: ubiquinone oxidoreductase core subunit V1 (NDUFV1) is an important subunit of mitochondrial complex I. In the present study, we found that NDUFV1 was reduced in kidneys of renal ischemia/reperfusion (I/R) mice. Meanwhile, renal I/R induced kidney dysfunction as evidenced by increases in BUN and serum creatinine, severe injury of proximal renal tubules, oxidative stress, and cell apoptosis. All these detrimental outcomes were attenuated by increased expression of NDUFV1 in kidneys. Moreover, knockdown of Ndufv1 aggravated cell insults induced by H2 O2 in TCMK-1 cells, which further confirmed the renoprotective roles of NDUFV1. Mechanistically, NDUFV1 improved the integrity and function of mitochondria, leading to reduced oxidative stress and cell apoptosis. Overall, our data indicate that NDUFV1 has an ability to maintain mitochondrial homeostasis in AKI, suggesting therapies by targeting mitochondria are useful approaches for dealing with mitochondrial dysfunction associated renal diseases such as AKI.

A cryptic pathogenic NDUFV1 variant identified by RNA-seq in a patient with normal complex I activity in muscle and transient magnetic resonance imaging changes.

Mitochondrial respiratory chain disorders (MRC) are amongst the most common group of inborn errors of metabolism. MRC, of which complex I deficiency accounts for approximately a quarter, are very diverse, causing a wide range of clinical problems and can be difficult to diagnose. We report an illustrative MRC case whose diagnosis was elusive. Clinical signs included failure to thrive caused by recurrent vomiting, hypotonia and progressive loss of motor milestones. Initial brain imaging suggested Leigh syndrome but without expected diffusion restriction. Muscle respiratory chain enzymology was unremarkable. Whole-genome sequencing identified a maternally inherited NDUFV1 missense variant [NM_007103.4 (NDUFV1):c.1157G > A; p.(Arg386His)] and a paternally inherited synonymous variant [NM_007103.4 (NDUFV1):c.1080G > A; (p.Ser360=)]. RNA sequencing demonstrated aberrant splicing. This case emphasizes the diagnostic odyssey of a patient in whom a confirmed diagnosis was elusive because of atypical features and normal muscle respiratory chain enzyme (RCE) activities, along with a synonymous variant, which are often filtered out from genomic analyses. It also illustrates the following points: (1) complete resolution of magnetic resonance imaging changes may be part of the picture in mitochondrial disease; (2) analysis for synonymous variants is important for undiagnosed patients; and (3) RNA-seq is a powerful tool to demonstrate pathogenicity of putative splicing variants.

Compound heterozygous mutations of NDUFV1 identified in a child with mitochondrial complex I deficiency.

BACKGROUND: Mitochondrial complex I deficiency (MCID) is the most common biochemical defect identified in childhood with mitochondrial diseases, mainly including Leigh syndrome, encephalopathy, macrocephaly with progressive leukodystrophy, hypertrophic cardiomyopathy and myopathy. OBJECTIVE: To identify genetic cause in a patient with early onset autosomal recessive MCID. METHODS: Trio whole-exome sequencing was performed and phenotype-related data analyses were conducted. All candidate mutations were confirmed by Sanger sequencing. RESULTS: Here we report a child of Leigh syndrome presented with global developmental delay, progressive muscular hypotonia and myocardial damage. A missense mutation c.118C > T (p.Arg40Trp) and a previously reported mutation c.1157G > A (p.Arg386His) in NDUFV1 have been identified as compound heterozygous in the patient. The mutation p.Arg386His is closely associated with the impairment of 4Fe-4S domain and this mutation has been reported pathogenic. The c.118C > T mutation has not been reported in ClinVar and HGMD database. In silico protein analyses showed that p.Arg40 is highly conserved in a wide range of species, and the amino acid substitution p.Trp40 largely decreases the stability of NDUFV1. In addition, the mutation has not been detected in the Asian populations and it was predicted to be deleterious by numerous prediction tools. CONCLUSION: This research expands the mutation spectrum of NDUFV1 and substantially provides an early and accurate diagnosis basis of MCID, which would benefit subsequently effective genetic counseling and prenatal diagnosis for future reproduction of the family.

Overexpression of NDUFV1 alleviates renal damage by improving mitochondrial function in unilateral ureteral obstruction model mice.

Mitochondrial homeostasis plays essential role for the proper functioning of the kidney. NADH-ubiquinone oxidoreductase core subunit V1 (NDUFV1) is an enzyme in the complex I of electron transport chain (ETC) in mitochondria. In the present study, we examined the effects of NDUFV1 on renal function in unilateral ureteral obstruction (UUO) model mice. Our data showed that increased expression of NDUFV1 improves kidney function as evidenced by the decreases in blood urea nitrogen and serum creatinine in UUO mice. Moreover, NDUFV1 also maintains renal structures and alleviates renal fibrosis induced by UUO surgery. Mechanistically, NDUFV1 mitigates the increased oxidative stress in the kidney in UUO model mice. Meanwhile, increased expression of NDUFV1 in the kidney improves the integrity of the complex I and potentiates the complex I activity. Overall, these results indicate that the ETC complex I plays a beneficial role against renal dysfunction induced by acute kidney injury such as UUO. Therefore, NDUFV1 might be a druggable target for developing agents for dealing with disabled mitochondria-associated renal diseases.

The FoxQ1 transcription factor is a novel regulator of electron transport chain complex I subunits in human breast cancer cells.

The FoxQ1 is an oncogenic transcription factor that is overexpressed in basal-like and luminal-type human breast cancers when compared to the normal mammary tissue. The FoxQ1 is implicated in mammary tumor progression. However, the mechanism by which FoxQ1 promotes mammary tumorigenesis is not fully understood. In this study, we present experimental evidence for a novel function of FoxQ1 in the regulation of complex I activity of the electron transport chain. The RNA-seq data from FoxQ1 overexpressing basal-like SUM159 cells revealed a statistically significant increase in the expression of complex I subunits NDUFS1 and NDUFS2 when compared to the empty vector (EV) transfected control cells. Consistent with these results, the basal and ATP-linked oxygen consumption rates were significantly increased by FoxQ1 overexpression in SUM159 and luminal-type MCF-7 cells. The FoxQ1 overexpression in both cell lines resulted in increased intracellular levels of pyruvate, lactate, and ATP that was associated with overexpression of pyruvate dehydrogenase and pyruvate carboxylase proteins. Activity and assembly of complex I were significantly enhanced by FoxQ1 overexpression in SUM159 and MCF-7 cells that correlated with increased mRNA and/or protein levels of complex I subunits NDUFS1, NDUFS2, NDUFV1, and NDUFV2. The chromatin immunoprecipitation assay revealed the recruitment of FoxQ1 at the promoters of both NDUFS1 and NDUFV1. The cell proliferation of SUM159 and MCF-7 cells was increased significantly by overexpression of NDUFS1 as well as NDUFV1 proteins. In conclusion, we propose that increased complex I-linked oxidative phosphorylation is partly responsible for oncogenic role of FoxQ1 at least in human breast cancer cells.

[A novel frameshift NDUFV1 mutation in a child with the phenotype of optic nerve atrophy].

OBJECTIVE: To investigate the pathogenic gene in a child with optic atrophy and analyze the influence of this gene mutation on protein structure. OBJECTIVE: We collected the clinical record of the 13-year-old girl and her relatives. The child received examinations of the visual acuity, visual field, fundus, OCT, visual-evoked potential (VEP) and the nerve system, underwent brain MRI and was followed up for 1 year. Genomic DNA was extracted from the peripheral blood of the child and her parents for next-generation sequencing of the whole exon. The pathogenic gene mutation was identified and the resultant changes in the protein structure was analyzed. OBJECTIVE: The patient presented with impaired vision and optic nerve atrophy in both eyes with low amplitude of VEP, but did not show dystonia or pyramidal tract symptom. Brain MRI detected no leukodystrophy. Genetic analysis suggested a heterozygous c.53_54delTG mutation in exon 1 in the NDUFV1 gene of complex I, which caused a frameshift starting with the codon valine 18, thus changing the amino acid to an Alanine residue and creating a premature stop codon at position 20 of the new reading frame (p.Val18AlafsX20). A heterozygous for c.1162+4A>C: IVS8 + 4A>C in intron 8 was also found. Protein structure analysis showed the missing of important structure of NDUFV1 subunit in complex I. OBJECTIVE: We identified a novel NDUFV1 mutation in a child with optic nerve atrophy. This finding may provide further insight into the genotype-phenotype correlations for NDUFV1 gene.

Leigh Syndrome Due to NDUFV1 Mutations Initially Presenting as LBSL.

Leigh syndrome (LS) is most frequently characterized by the presence of focal, bilateral, and symmetric brain lesions Leukoencephalopathy with brainstem and spinal cord involvement and lactate elevation (LBSL) is a rare condition, characterized by progressive pyramidal, cerebellar, and dorsal column dysfunction. We describe a case with infantile-onset neurodegeneration, psychomotor retardation, irritability, hypotonia, and nystagmus. Brain MRI demonstrated signal abnormalities in the deep cerebral white matter, corticospinal and dorsal column tracts, and pyramids, which resemble the MRI pattern of a severe form of LBSL, and involvement of basal ganglia and thalamus that resemble the radiological features of LS. We identified biallelic loss-of-function mutations, one novel (c.756delC, p.Thr253Glnfs*44) and another reported (c.1156C > T, p.Arg386Cys), in NDUFV1 (NADH:Ubiquinone Oxidoreductase Core Subunit V1) by exome sequencing. Biochemical and functional analyses revealed lactic acidosis, complex I (CI) assembly and enzyme deficiency, and a loss of NDUFV1 protein. Complementation assays restored the NDUFV1 protein, CI assembly, and CI enzyme levels. The clinical and radiological features of this case are compatible with the phenotype of LS and LBSL associated with NDUFV1 mutations.

Targeting Human Lung Adenocarcinoma with a Suppressor of Mitochondrial Superoxide Production.

Aims: REDOX signaling from reactive oxygen species (ROS) generated by the mitochondria (mitochondrial reactive oxygen species [mtROS]) has been implicated in cancer growth and survival. Here, we investigated the effect of 5-(4-methoxyphenyl)-3H-1,2-dithiole-3-thione (AOL), a recently characterized member of the new class of mtROS suppressors (S1QELs), on human lung adenocarcinoma proteome reprogramming, bioenergetics, and growth. Results: AOL reduced steady-state cellular ROS levels in human lung cancer cells without altering the catalytic activity of complex I. AOL treatment induced dose-dependent inhibition of lung cancer cell proliferation and triggered a reduction in tumor growth in vivo. Molecular investigations demonstrated that AOL reprogrammed the proteome of human lung cancer cells. In particular, AOL suppressed the determinants of the Warburg effect and increased the expression of the complex I subunit NDUFV1 which was also identified as AOL binding site using molecular modeling computer simulations. Comparison of the molecular changes induced by AOL and MitoTEMPO, an mtROS scavenger that is not an S1QEL, identified a core component of 217 proteins commonly altered by the two treatments, as well as drug-specific targets. Innovation: This study provides proof-of-concept data on the anticancer effect of AOL on mouse orthotopic human lung tumors. A unique dataset on proteomic reprogramming by AOL and MitoTEMPO is also provided. Lastly, our study revealed the repression of NDUFV1 by S1QEL AOL. Conclusion: Our findings demonstrate the preclinical anticancer properties of S1QEL AOL and delineate its mode of action on REDOX and cancer signaling.

Late-Onset Leigh Syndrome due to NDUFV1 Mutation in a 10-Year-Old Boy Initially Presenting with Ataxia.

Leigh syndrome (LS) is a progressive neurodegenerative disease caused by either mitochondrial or nuclear DNA mutations resulting in dysfunctional mitochondrial energy metabolism. The onset of clinical features is typically between 3 and 12 months of age; however, a later onset has been described in a few patients. Complex I deficiency is reported to be the most common cause of mitochondrial disorders. We described a patient with a late-onset LS, who presented with gait ataxia, caused by complex I deficiency (NDUFV1 gene).

Cystic Leucoencephalopathy in NDUFV1 Mutation.

Complex I deficiency is one of the most common mitochondrial respiratory chain defect. This deficiency of oxidative phosphorylation results from mutation in nuclear and mitochondrial DNA. Mutations in NDUFV1 (Flavin binding subunit of Respiratory complex 1) results in neurological manifestations including Leigh syndrome and leucoencephalopathy. The authors report a one-year-old boy with history of regression of motor milestones following a trivial fall from the bed. His magnetic resonance imaging revealed diffuse, cystic leucoencephalopathy involving corpus callosum and periventricular white matter. Clinical features and radiological findings may resemble those of vanishing white matter disease. Next generation sequencing revealed likely compound heterozygous missense pathogenic variant in exon 8 of NDUFV1 gene [c.1156C > C/T (p.Arg386Cys)] and possibly novel splice site variation in intron 2 of NDUFV1 gene (c.155 + 1G > G/A). NDUFV1 related leucoencephalopathy must be considered among those presenting with sudden onset of motor regression with neuroimaging correlate of diffuse cystic leucodystrophy.

[Progressive cavitating leukoencephalopathy: four cases and literatures review].

Objective: To analyze the clinical and genetic features of progressive cavitating leukoencephalopathy (PCL). Method: The data of clinical and genetic features of 4 PCL patients diagnosed by Beijing Children's Hospital between January 2015 and January 2016 were analyzed. The cases with complete clinical data retrieved on literature search at China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and PubMed (up to August 2016) by using search terms of"NDUFV1" ,"NDUFS1" , or"leukoencephalopathy" , were summarized. Result: There were three females and one male, two of which were compatriots. The age of onset ranged from 6 months to 15 months. All four children's first symptoms were motor development regression, and the developmental milestones were almost normal before the onset. Of the 4 patients, 3 had cognitive impairment, 1 had seizures, 4 had dystonia and pyramidal impairment, 2 had emaciation, and 1 had nystagmus. The lactate concentrations of 4 patients were normal in blood. One patient had lactaciduria in the urinary organic acid analysis. Cranial magnetic resonance imaging (MRI) of all patients showed leukoencephalopathy, involved in the corpus callosum, and three patients accompanied by cystic lesions. Follow up for 2-13 years showed that the physical and language development were improved. Genetic analysis revealed that mutations in NDUFS1 were found in three patients and NDUFV1 mutation was found in one patient. All six mutations (p.Arg377Cys and p. Arg377His in NDUFV1; p. Arg482Glyfs(*)5, p.Thr368Pro, p.Tyr454X and p. Asp565Gly in NDUFS1) are novel. Five English case reports including 10 PCL patients were collected. Together with this group of 4 cases, a total of 14 cases were involved. All 14 children patients had motor development regression, 11 cases had cognitive impairment and dystonia, 6 cases had pyramidal impairment, 5 cases had irritability, 4 cases had epilepsy and nystagmus, 3 cases had strabismus and swallowing difficulty. Cranial MRI showed patchy leukoencephalopathy with cavities, involved in the corpus callosum. Follow up for 19 months-15 years that the neurology development were improved slowly in all patients. Conclusion: NDUFS1 and NDUFV1 gene mutation screening should be performed firstly in patients with PCL clinical and imaging feature.

Whole Exome Sequencing Identifies the Genetic Basis of Late-Onset Leigh Syndrome in a Patient with MRI but Little Biochemical Evidence of a Mitochondrial Disorder.

Leigh syndrome is a subacute necrotising encephalomyopathy proven by post-mortem analysis of brain tissue showing spongiform lesions with vacuolation of the neuropil followed by demyelination, gliosis and capillary proliferation caused by mutations in one of over 75 different genes, including nuclear- and mitochondrial-encoded genes, most of which are associated with mitochondrial respiratory chain function. In this study, we report a patient with suspected Leigh syndrome presenting with seizures, ptosis, scoliosis, dystonia, symmetrical putaminal abnormalities and a lactate peak on brain MRS, but showing normal MRC enzymology in muscle and liver, thereby complicating the diagnosis. Whole exome sequencing uncovered compound heterozygous mutations in NADH dehydrogenase (ubiquinone) flavoprotein 1 gene (NDUFV1), c.1162+4A>C (NM_007103.3), resulting in skipping of exon 8, and c.640G>A, causing the amino acid substitution p.Glu214Lys, both of which have previously been reported in a patient with complex I deficiency. Patient fibroblasts showed a significant reduction in NDUFV1 protein expression, decreased complex CI and complex IV assembly and consequential reductions in the enzymatic activities of both complexes by 38% and 67%, respectively. The pathogenic effect of these variations was further confirmed by immunoblot analysis of subunits for MRC enzyme complexes in patient muscle, liver and fibroblast where we observed 90%, 60% and 95% reduction in complex CI, respectively. Together these studies highlight the importance of a comprehensive, multipronged approach to the laboratory evaluation of patients with suspected Leigh syndrome.

Progressive cavitating leukoencephalopathy: four cases and literatures review / 中华儿科杂志

Objective@#To analyze the clinical and genetic features of progressive cavitating leukoencephalopathy (PCL).@*Method@#The data of clinical and genetic features of 4 PCL patients diagnosed by Beijing Children′s Hospital between January 2015 and January 2016 were analyzed. The cases with complete clinical data retrieved on literature search at China National Knowledge Infrastructure, Wanfang Data Knowledge Service Platform and PubMed (up to August 2016) by using search terms of"NDUFV1" ,"NDUFS1" , or"leukoencephalopathy" , were summarized.@*Result@#There were three females and one male, two of which were compatriots. The age of onset ranged from 6 months to 15 months. All four children′s first symptoms were motor development regression, and the developmental milestones were almost normal before the onset. Of the 4 patients, 3 had cognitive impairment, 1 had seizures, 4 had dystonia and pyramidal impairment, 2 had emaciation, and 1 had nystagmus. The lactate concentrations of 4 patients were normal in blood. One patient had lactaciduria in the urinary organic acid analysis. Cranial magnetic resonance imaging (MRI) of all patients showed leukoencephalopathy, involved in the corpus callosum, and three patients accompanied by cystic lesions. Follow up for 2-13 years showed that the physical and language development were improved. Genetic analysis revealed that mutations in NDUFS1 were found in three patients and NDUFV1 mutation was found in one patient. All six mutations (p.Arg377Cys and p. Arg377His in NDUFV1; p. Arg482Glyfs*5, p.Thr368Pro, p.Tyr454X and p. Asp565Gly in NDUFS1) are novel. Five English case reports including 10 PCL patients were collected. Together with this group of 4 cases, a total of 14 cases were involved. All 14 children patients had motor development regression, 11 cases had cognitive impairment and dystonia, 6 cases had pyramidal impairment, 5 cases had irritability, 4 cases had epilepsy and nystagmus, 3 cases had strabismus and swallowing difficulty. Cranial MRI showed patchy leukoencephalopathy with cavities, involved in the corpus callosum. Follow up for 19 months-15 years that the neurology development were improved slowly in all patients.@*Conclusion@#NDUFS1 and NDUFV1 gene mutation screening should be performed firstly in patients with PCL clinical and imaging feature.

Broad phenotypic variability in patients with complex I deficiency due to mutations in NDUFS1 and NDUFV1.

We report clinical, metabolic, genetic and neuroradiological findings in five patients from three different families with isolated complex I deficiency. Genetic analysis revealed mutations in NDUFS1 in three patients and in NDUFV1 in two patients. Four of the mutations are novel and affect amino acid residues that either are invariant among species or conserved in their properties. The presented clinical courses are characterized by leukoencephalopathy or early death and expand the already heterogeneous phenotypic spectrum. A literature review was performed, showing that patients with mutations in NDUFS1 in general have a worse prognosis than patients with mutations in NDUFV1.

Mitochondrial proteome remodeling in ischemic heart failure.

AIMS: Mitochondrial dysfunction is an important part of the decline in cardiac function in heart failure. We hypothesized for hypothesized that there would be specific abnormalities in mitochondrial function and proteome with the progression of ischemic heart failure (HF). MAIN METHODS: We used a high left anterior descending artery (LAD) ligation in 3-4month old male rats to generate HF. Rats were studied 9weeks post-ligation. KEY FINDINGS: Electron microscopy of left ventricle samples showed mitochondrial changes including decreased size, increased number, abnormal distribution, and cristae loss. Mitochondria in ischemic HF exhibited decreased total ATP, impaired mitochondrial respiration, as well as reduced complex I activity. Analysis of LV mitochondrial proteins by mass spectrometry was performed, and 31 differentially expressed proteins (p<0.05) of more than 500 total proteins were identified. Of these proteins, 15 were up-regulated and 16 were down-regulated in the failing heart. A set of complex I proteins was significantly decreased, consistent with the impairment of complex I activity. There were distinct changes in mitochondrial function and proteome in ischemic HF. Although there were similarities, the distinction between the reported proteomic changed with TAC pressure overload induced HF and ischemic HF in the current study suggested different pathological mechanisms. SIGNIFICANCE: Specific changes in mitochondrial protein expression, which correlate with changes in mitochondrial function, have been identified in ischemic HF for the first time.

A novel familial case of diffuse leukodystrophy related to NDUFV1 compound heterozygous mutations.

NDUFV1 mutations have been related to encephalopathic phenotypes due to mitochondrial energy metabolism disturbances. In this study, we report two siblings affected by a diffuse leukodystrophy, who carry the NDUFV1 c.1156C>T (p.Arg386Cys) missense mutation and a novel 42-bp deletion. Bioinformatic and molecular analysis indicated that this deletion lead to the synthesis of mRNA molecules carrying a premature stop codon, which might be degraded by the nonsense-mediated decay system. Our results add information on the molecular basis and the phenotypic features of mitochondrial disease caused by NDUFV1 mutations.